1. Field of the Invention
The present invention relates to an apparatus and method used in fingerprint identification for extracting minutia data (characteristic point data) from a fingerprint image data.
2. Description of the Related Arts
In personal identification systems using fingerprint identification, a fingerprint identification method has been proposed to ensure the correctness of the registered fingerprint data in which minutiae (characteristic points) having a high frequency of appearance are adopted as the registered data. Usually, the minutia is an end point or a branch point of a ridge line of a fingerprint.
In this method, the optical picking-up of the fingerprint data using the same fingerpad (the palm side of a human fingertip) is carried out repeatedly, assigning the appearance frequency to each minutia, selecting a predetermined number of the minutiae from those having the highest appearance frequency to those having lower appearance frequencies, and adopting the thus selected minutiae as the data to be registered.
In this method, however, since a plurality of operations of picking-up of the fingerprint image using the same fingerpad are required, it is troublesome for the person whose fingerprint is being picked up to carry out such a plurality of picking-up operations, and further, it is necessary to carry out an alignment between minutiae because the location of the second operation of pressing down of the fingerprint after the lifting of the fingerprint after the first operation of pressing down of the fingerprint does not usually coincide with the location of the fingerprint in the first pressing down operation.